Squeeze Bearing Research Articles

S1105-1-1 高速度カメラによるスラストスクイーズ軸受の油膜破断観察([S1105-1]トライボロジーの基礎と応用(1))

S1105-1-1 高速度カメラによるスラストスクイーズ軸受の油膜破断観察([S1105-1]トライボロジーの基礎と応用(1))

906 超音波スクイーズ案内の浮上特性および動特性の把握と理論的検討(GS-11 トライボロジ(1))

906 超音波スクイーズ案内の浮上特性および動特性の把握と理論的検討(GS-11 トライボロジ(1))

Design and Nanomotion Control of a Noncontact Stage with Squeeze Bearings

As the need to develop high-performance highly accurate positioning has grown in a wide range of industries, it has become necessary to comprehensively study desirable stage positioning systems based on new design concepts. Achieving nanometer positioning requires simultaneous noncontact drive and support of the moving stage. We developed a linear motordriven stage positioning system with squeeze bearings and evaluated squeeze bearing and positioning performance of the proposed positioning system through a series of actual stage driving experiments that confirmed the stage's nanopositioning capability.

A Newly Developed Compact Nano-Positioning Table System Using Squeeze Bearing

A Newly Developed Compact Nano-Positioning Table System Using Squeeze Bearing

Floating Characteristics of Squeeze-Film Gas Bearings With Vibration Absorber for Linear Motion Guide

This paper describes the floating characteristics of squeeze-film gas bearings with a vibration absorber. This bearing uses a piezoelectric actuator directly attached to a counterweight to impart oscillations to a bearing surface and, therefore, can generate a squeeze-film between the bearing and the guideway surfaces. Furthermore, in this squeeze bearing, a vibration absorber is inserted between a counterweight and a carried object to reduce the vibrational amplitude of the carried object and improve the motion accuracy. The effects of the vibration absorber on the floating characteristics are discussed theoretically and experimentally. It was found that the material of the vibration absorber greatly affected the floating characteristics, and the absorber made of silicone rubber was very effective to reduce the vibrational amplitude of the carried object.

Fluid film lubrication with nonlinear four-element viscoelastic fluids. Finite-width journal bearings and parallel circular bearings in normal approach.

A modified Reynolds equation for nonlinear viscoelastic fluids based on a nonlinear four-element model was derived, and the effects of viscoelastic behavior on the performance of parallel circular squeeze bearings oscillated sinusoidally was clarified by comparing the theoretical results with the experimental ones, in the previous paper. This paper presents two applications of the modified Reynolds equation to fluid film lubrication problems. Firstly, by applying the modified Reynolds equation to a finite-width journal bearing which is oscillated sinusoidally, the analytical procedure for viscoelastic lubrication problems under three-dimensional flows of lubricants is clarified, and good agreement is shown between the experimental results and the theoretical predictions based on the four-element model. Secondly, to clarify the effects of viscoelastic behavior on the performance of parallel circular bearings under irregular squeeze motion, theoretical and experimental studies of parallel circular plates in normal approach are shown.

Fluid film lubrication with nonlinear four-element viscoelastic fluids. (Flow characteristics, a modified reynolds equation and its application to parallel circular squeeze bearings)

The objective of this study is to establish an analytical procedure for viscoelastic fluid film lubrication based on a nonlinear four-element model, which should apply to lubricating oils containing a large quantity of high molecular-weight polymers. It is made clear from the flow characteristic test that the viscoelastic behavior of such lubricants is represented by a rheology equation based on a four-element model which consists of two nonlinear dashpots and two nonlinear springs. A modified Reynolds equation for finite-width bearings is derived by employing the nonlinear rheology equation. The effects of nonlinear viscoelastic characteristics on the film pressure are then studied with a parallel circular squeeze bearing, and it is shown that the experimental results agree well with the theoretical predictions.

Fluid film lubrication with nonlinear four-element viscoelastic fluids. (3rd report. Parallel circular bearings in normal approach).

In the first paper, a modified Reynolds equation for nonlinear viscoelastic fluids based on nonlinear four-element model was derived. In the second paper, the effects of viscoelastic behavior on the performance of parallel circular squeeze bearings oscillated sinusoidally was clarified by comparing theoretical results with experimental ones. This paper presents theoretical and experimental studies on fluid film lubrication with nonlinear viscoelastic lubricants between parallel circular plate in normal approach. As the upper plate of the parallel circular bearings falls by its own weight, the film pressure and the film thickness are calculated by solving simultaneously the modified Reynolds equation and the equation of motion of the upper plate. In addition, the experiments using the viscoelastic fluids as lubricants are carried out, and it is found that the experimental results are in good agreement with the theoretical ones.

Inertia effect of micropolar fluid in squeeze bearings and thrust bearings

A theoretical study is made of squeeze films between two infinitely long rectangular plates and between circular plates, and of a thrust bearing, assuming the lubricant to be a micropolar fluid. The effect of inertia is considered and the effects of the material constants of the fluid on the bearing characteristics are discussed. The effect of inertia is to increase the time of approach for squeeze bearings and to diminish the load capacity for thrust bearings. For squeeze bearings, the time of approach is greater with a micropolar fluid than with a Newtonian fluid and, for thrust bearings, the load capacity is greater with a micropolar fluid than with a Newtonian fluid.

Stability of Rotor-Bearing Systems With Generalized Support Flexibility and Damping and Aerodynamic Cross-Coupling

This paper examines stability of the flexible single mass rotor, acted on by motion induced forces due to aero-dynamic cross-coupling and supported most generally by oil film tilting pad bearings which are in turn mounted on flexible, damped supports. Plotted results include the frequency dependent spring and damping coefficients for the 4-pad tilting pad bearing, damping coefficients for the 360-deg squeeze bearing and stability plots of rotor-bearing systems including aerodynamic cross-coupling, the 4-pad tilting pad bearing and the 150-deg partial arc bearing with various support arrangements.

Asymptotic Methods for an Infinitely Long Step Slider Squeeze Bearing

The step slider squeeze bearing is analyzed by a combination of singular perturbation techniques and numerical procedures. It is assumed that the bearing number associated with the trailing section is large and that the amplitude of the squeezing motion is small. There is no restriction on the film clearance or the jump in the film thickness at the step, so the bearing number associated with the leading section of the bearing need not be large. Results for the steady-state load are given for several geometries. Stability characteristics of different geometries are discussed.

Compressible Squeeze Films and Squeeze Bearings

Experimental agreement with a finite-difference solution of the isothermal squeeze film equation was obtained for steady-state sinusoidal squeeze motion of parallel, coaxial disks. At low squeeze number, the film force is in phase with the velocity; at high squeeze number, with the displacement. Compressibility effects at high squeeze number introduce a superambient mean film pressure, so that it is possible to operate a gas bearing on squeeze effects alone. Thrust bearings, spherical bearings, and journal bearings have been successfully operated as squeeze bearings, using both electromagnetic and piezoelectric devices to generate the squeeze motion.